Advances in technology have provided users of computing devices with the ability to instantaneously and seamlessly share media content (i.e., photos, videos, documents, among other file types) between different devices of a user and/or different users (e.g., friends and family) with many different technology companies providing various platforms for engaging in such activities. For example, social media has permitted the instantaneous sharing of photos and videos across mobile devices, desktop computers, tablets, and many other types of devices with different video playback capabilities. Other cloud based storage platforms have allowed users to share content by providing, for example, a URL to a location of content to other users with whom they would like to share content. Different services may use different technology implementations to deliver content to users. Technology providers often consider many different factors when implementing a particular content delivery mechanism including, but not limited to, the storage required to store content on a platform, the processing necessary to stream content to different devices, network considerations including bandwidth requirements, and the amount of latency experienced by mobile devices in viewing content. Furthermore, with the rapid progress in the quality of videos available, these considerations become ever more vital when implementing a particular technology standard.
In general, video content may be delivered to user device by streaming and/or downloading. The term streaming media describes the playback of media on a playback device, where the media is stored on a server and continuously sent to the playback device over a network during playback. Typically, the playback device stores a sufficient quantity of media in a buffer at any given time during playback to prevent disruption of playback due to the playback device completing playback of all the buffered media prior to receipt of the next portion of media. Adaptive bit rate streaming or adaptive streaming involves detecting the present streaming conditions (e.g. the playback device's network bandwidth and video decoding capacity) in real time and adjusting the quality of the streamed media accordingly. Typically, the source media is encoded as separate streams having different maximum bitrates and the playback device or client switches between streaming the different encodings depending on available resources. When a playback device commences adaptive bitrate streaming, the playback device typically starts by requesting portions of media from an initial set of streams. As the playback device downloads the requested media, the playback device can measure the available bandwidth. In the event that the available bandwidth increases or decreases, the playback device can switch to higher or lower bitrate streams.
Adaptive streaming solutions typically utilize Hypertext Transfer Protocol (HTTP), published by the Internet Engineering Task Force and the World Wide Web Consortium as RFC 2616, to stream media between a server and a playback device. HTTP is a stateless protocol that enables a playback device to request a byte range within a file. HTTP is described as stateless, because the server is not required to record information concerning the state of the playback device requesting information or the byte ranges requested by the playback device in order to respond to requests received from the playback device.
In adaptive streaming systems, the source media is typically stored on a media server as a top level index file pointing to a number of alternate streams that contain the actual video and audio data. Each stream is typically stored in one or more container files. Different adaptive streaming solutions typically utilize different index and media containers. The Synchronized Multimedia Integration Language (SMIL) developed by the World Wide Web Consortium is utilized to create indexes in several adaptive streaming solutions including IIS Smooth Streaming developed by Microsoft Corporation of Redmond, Wash., and Flash Dynamic Streaming developed by Adobe Systems Incorporated of San Jose, Calif. HTTP Adaptive Bitrate Streaming developed by Apple Computer Incorporated of Cupertino, Calif. implements index files using an extended M3U playlist file (.M3U8), which is a text file containing a list of URIs that typically identify a media container file. The most commonly used media container formats are the MP4 container format specified in MPEG-4 Part 14 (i.e. ISO/IEC 14496-14) and the MPEG transport stream (TS) container specified in MPEG-2 Part 1 (i.e. ISO/IEC Standard 13818-1). The MP4 container format is utilized in IIS Smooth Streaming and Flash Dynamic Streaming. The TS container is used in HTTP Adaptive Bitrate Streaming.